• International journal of advanced smart convergence
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• v.4 no.2
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• pp.38-45
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• 2015

Peer-to-Peer(P2P) systems are generally classified into two categories; hybrid and pure P2P. Hybrid systems have a single central index server keeping the details of shared information, so that undesirable effects such as heavy load on that server and lack of fault-tolerance can be caused. Pure P2P causes the other problems such as message flooding and scalability although it shows high degree of fault-tolerance. Recently, mobile agent-based distributed computing has been receiving wide attention for its potential to support disconnected operations, high asynchrony, and thus saving network bandwidth. In this paper, a new scheme of peer coordination is proposed for a decentralized P2P network with self-organizing structure. We deployed mobile agents for incorporating the advantages of usage of mobile agents into our P2P network. Proposed P2P network has both advantages of hybrid and pure P2P. The problems of heavy load on the server and lack of fault-tolerance are improved by using multiple special peers called super-peers. And the problems of pure P2P can be reduced by using mobile agents.

• Korean Journal of Plant Resources
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• v.32 no.4
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• pp.296-302
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• 2019

This study was accomplished to select breeding materials among the pear germplasm 6 species 43 accessions and check out the expression of scab incidence of inter specific hybrids of 5 crosses 609 seedlings for scab resistance breeding. Fruitlets scab incidence of P. pyrifolia, P. bretschneideri and P. ussuriensis were 59.5, 73.4 and 63.0% respectively, and also fruitlets scab incidence of interspecific hybrid cultivars between P. pyrifolia and P. bretschneideri were 77.7%. However, fruitlets scab incidence of P. communis and interspecific hybrid accessions between P. pyrifolia and P. communis were significantly less than 15%. As a result of the Duncan test, scab resistance of pear accessions were classified into two groups: P. communis and their hybrid were resistance and P. bretschneideri, P. pyrifolia, P. ussuriensis, and among their hybrid were susceptible. Also, it showed the same trend in the seedlings. Scab incidence of 'Seolwon' ${\times}$ 'Chuwhangbae' and 'Supergold' ${\times}$ 'Mantienhong' in P. pyrifolia seedlings showed more than 80%, while that of interspecific hybrid between P. pyrifolia and P. communis showed about 2%. It showed scab resistance of P. communis transferred to hybrid seedlings and expressed to be dominant in their seedlings. Namely, P. communis was good breeding materials for scab resistance.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.40-42
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• 2004

Access Grid는 상호공동작업을 위하여 대용량의 컨텐츠 파일들을 주고받으며 공유한다. 특별히 중앙의 집중된 관리서버가 없는 Access Grid환경에서는 컨텐츠의 위치추적의 어려움, 부재, 병목 등의 현상이 발생하는데 이를 본 논문에서 1. 중앙 Hybrid서버의 구현 2. 집중컨텐츠의 거점노드복제 3. 중요컨텐츠의 24시간 공유보장 등의 기법으로 해결방안을 제안하였다. 그리고 이에 대한 효율성을 시뮬레이션 자료로 증명하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.73-81
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• 2020

Today's massively multiplayer online games(MMOGs) can contain millions of synchronous players scattered across the world and participating with each other within a single shared game. The increase in the number of players in MMOGs has led to some issues with the demand of server which generates a significant increase in costs for the game industry and impacts to the quality of service offered to players. In dealing with a considerable scale of MMOGs, we propose a cloud computing and peer-to-peer(P2P) hybrid architecture in this paper. Given the two nearly independent functionalities of P2P and cloud architectures, we consider the possibility of fusing these two concepts and researching the application of the resultant amalgamation in MMOGs. With an efficient and effective provisioning of resources and mapping of load, the proposed hybrid architecture relieves a lot of computational power and network traffic, the load on the servers in the cloud while exploiting the capacity of the peers. The simulation results show that MMOGs based on the proposed hybrid architecture have better performance and lower traffic received compared with MMOGs based on traditional client-server system.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.412-414
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• 2002

현재 많이 사용되고 있는 P2P개념으로는 순수 P2P와 변경 P2P구조가 있다[3]. 순수 P2P의 모델에는 Gnutella와 stella등의 형태가 존재하고 변형 P2P로는 무수히 많은 형태가 존재한다. 이 변형 P2P모델들 중파일 공유 모델들이 존재하는데 이 모델들은 파일의 공유를 위한 그룹 관리와 검색, 색인 등의 기능을 제공한다. 파일공유 모델의 Peer들에 대해 연결성 유지를 위한 많은 부하와 사용자에 있어서 그룹에 대한 형태의 문제점 그리고 서버의 Fail에 대한 비연결성에 관한 문제점을 해결하기 위해 본 논문에서는 라우팅 기법에서의 접근을 통해 과일공유모델에 계층적 구조를 적용하고 Backup시스템을 설계하여 사용자에 의한 효율적인 그룹관리와 연결의 신뢰성을 유지하기 위해 시스템을 설계하였다.

• Proceedings of the KIEE Conference
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• 2004.05a
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• pp.62-64
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• 2004

P2P Systems have grown dramatically in recent years. Now many P2P systems have developed and been confronted by P2P technical challenges. We should consider how to efficiently locate desired resources. In this paper we integrated the existing pure P2P and hybrid P2P model. We try to keep roles of super peer in hybrid and concurrently use pure P2P model for searching resource. In order to improve the existing search mechanism, we present contents-based classification mechanism. Proposed system have the following features. This can forward only query to best peer using RI. Second, it is self-organization. A peer can reconfigure network that it can communicate directly with based on best peer. Third, peers can cluster each other through contents-based classification.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.406-408
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• 2003

현재 많이 사용되고 있는 P2P 개념으로는 순수 F2P와 변형 F2P구조가 있다. 순수 P2P의 모델에는 Gnutella와 Ktella 등의 형태가 존재하고 변형 P2P로는 무수히 많은 형태가 존재한다. 순수 P2P 모델의 경우에는 정보 공유에서 연결성을 장점으로 Gnutella의 형태를 응용한 형태로 많이 사용되고 있지만 정보를 검색하거나 제공하기 위해 많은 트래픽을 소모하게 된다. 이와는 달리 변형 P2P모델들 중 정보 공유 모델들이 존재하는데 이 모델들은 사용자에게 효율적이고 빠른 검색과 색인을 제공하기 위해 기존의 서버/클라이언트 형태를 취하고 있지만 제공하는 서버의 능력에 의존할 수 밖에 없다. 파일공유 모델의 Peer들에 대해 연결성 유지를 위한 많은 부하와 사용자에 있어서 그룹에 대한 형태의 문제점 그리고 서버의 Fail로 인한 비 연결성에 대한 문제점을 해결하기 위해 본 논문에서는 라우팅 프로토콜 기법에서의 접근과 계층적 구조를 적용하고 Backup 시스템을 포함해서 효율적인 그룹관리와 동적인 서버의 지정으로 신뢰성을 유지하기 위한 시스템을 설계하고 구현하였다.

• Development and Reproduction
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• v.21 no.2
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• pp.181-191
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• 2017

A comparison of the growth, hematological values, fatty acids, and gonadal and growth hormonal changes of river puffer, Takifugu obscurus, tiger puffer, T. rubripes, their hybrids (river puffer ${\times}$ tiger puffer) and hybrid triploids was performed during 3 months of their early growth period. Several features were observed during these 3 months: hybrids showed the highest levels of specific growth rate, 1.48%; hybrid triploids showed the smallest change in viscera fat (P<0.05), but GSI was not significantly different among groups (P>0.05). Considering hematological parameters, hybrid triploids had increased mean corpuscular volume and mean corpuscular hemoglobin (P<0.05), but other parameters were not significantly different between groups (P>0.05). With respect to fatty acids, puffer fish, hybrids and hybrid triploids contained fatty acids such as SFAs, MUFAs, n-3 PUFAs and n-6 PUFAs. There were significantly different amounts of total fatty acids between groups (P<0.05), however, rates of changes in fatty acids did not differ significantly between groups (P>0.05). Gonadal hormone (estradiol and testosterone) changes in the river puffer and tiger puffer were significantly higher than that observed in hybrids and hybrid triploids. The hybrids and tiger puffers had higher amounts of growth hormone (thyroid stimulating hormone and thyroxine) than the hybrid triploids and river puffers (P<0.05).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.1035-1056
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• 2015

The efficiency of live Peer-to-Peer (P2P) streaming protocols depends on the appropriateness and the management abilities of their underlying overlay multicast. While a tree overlay structure confines transmission delays efficiently by maintaining deterministic delivery paths, an overlay mesh structure provides adequate resiliency to peers dynamics and easy maintenance. On the other hand, content freshness, playback fluidity and streaming continuity are still challenging issues that require viable solutions. In this paper, we propose a Hybrid Live P2P Streaming Protocol (HLPSP) based on a hybrid overlay multicast that integrates the efficiency of both the tree and mesh structures. Extensive simulations using OMNET++ are conducted to investigate the efficiency of HLPSP in terms of relevant performance metrics, and position HLPSP with respect to DenaCast the enhanced version of the well-known CoolStreaming protocol. Simulation results show that HLPSP outperforms DenaCast in terms of startup delay, end-to-end delay, play-back delay and data loss.

• Journal of the Korea Society of Computer and Information
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• v.24 no.11
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• pp.11-19
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• 2019

Recently, hybrid CDN/P2P video streaming architecture is specially designed and deployed to achieve the scalability of P2P networks and the desired low delay and high throughput of CDNs. In this paper, we propose a cooperative video streaming and active node buffer management technique in hybrid CDN/P2P architecture. The key idea of this streaming strategy is to minimize network latency such as jitter and packet loss and to maximize the QoS(quality of service) by effectively and efficiently utilizing the information sharing of file location in CDN's proxy server which is an end node located close to a user and P2P network. Through simulation, we show that the proposed cooperative video streaming and active node buffer management technique based on CDN and P2P network improves the performance of realtime video streaming compared to previous methods.